Coring bit



May 15, 1951 H. G. BENrsoN CORING BIT F'led Oct. l1, i948 2 Sheets-Sheet 1 O L?? 02a.

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May 15, 1951 H. G. BEN'rsoN 2,553,032

CORING BIT Filed Oct. 11, 1948 2 Sheets-Sheet 2 l man@ *a* ISC ,Hp/90a? G. 35A/MON, INVEN TOR.

Patented May 1.5, .1951

CORING BIT Harold G. Bentson, Whittier, Calif., assignor to Security Engineering Co., Inc., Whittier, Calif., a corporation of California Application `October 11, 1948, Serial No. 53,859

7 Claims. (Cl. Z55-72) This invention relates to improvements in coring bits.

Heretofore coring bits have been devised wherein the core cut by the bit on passing up through the barrel of the bit is diverted laterally through a window or outlet in the side wall ofthe bit or coring drill collar being broken into relatively small pieces on being thus diverted and the small pieces flushed to the surface by the drilling fluid. Bits of this character are used to coninuously form the core, break it into relatively small pieces, and discharge it through the window or outlet until such time as occasion may require the withdrawal of the bit from the well. Usually this occurs when the cutters on the bit have become so worn and dull that they require replacement. At such time as the bit is withdrawn from the Well it is desirable to retain in the barrel of the bit and coring drill collar the remaining or residual core and to withdraw this core from the well with the bit so that from an inspection of the core thus obtained the nature of the formation that is being drilled through at the time that the bit was withdrawn can be determined.

Although it is highly desirable to retain and recover the small length of remaining or residual core in the barrel, it has been found that frequently when the bit is recovered thatY there is no remaining or residual core in the barrel.

I have determined that the loss of such cores is not due to the inability of the core catcher to retail the core in the barrel but is due to the fact that for one reason or another the core is forced out of the top of the barrel and deflected .f

through the window or outlet. This may be due to any one of a number of reasons such as the lowering of the bit in the well as is occasioned by setting the drill stem on slips on the rotary table in the course of uncoupling stands of drill pipe therefrom. When the bit is lowered in the well, the size of the bit is so close to the size of the well hole that in effect it may function somewhat as a large piston forcing the circulation uid in the well hole up against the core in the barrel and thus forcing the core out of the top of the barrel.

It is a primary object of the present invention to provide an improved coring bit of this character wherein provision is made for retarding or restraining upward movement of the residual or remaining core in the barrel so that it can not be forced out of the top thereof and through the window or outlet except forcibly by the forming of additional core thus assuring that the z residual or remaining core will be recovered with the bit on withdrawal of the bit from the well.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in` the appended claims, reference is had to the accompanying drawings foran illustrative embodiment of the invention, wherein:

Figure 1 is a vertical section through one form of coring bit and its coring drill collar embodying the present invention;

Fig. 2a is a vertical section on an enlarged scale of the upper half of the coring drill collar shown in Fig. 1;

Fig. 2b is a view in vertical section on an enlarged scale of the lower half of the coring drill collar and bit shown in Fig. 1;

Figs. 3, 4 and 5 are partial views in vertical section illustrating alternative forms of construction that may be employed; and

Fig. 6 is a horizontal section taken substantially upon the line 6 6 upon Fig. 5.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, I0 indicates a coring drill collar to which the bit head or bit proper I I is detachably secured. This bit is illustrated as being of the roller or rock bit type although any other conventional or preferred form of bit may be substituted therefor if desired. The cutters of the bit are designed to cut the walls of the well to gauge and to cut a central core which in the course of drilling and descent of the bit passes up through a central core hole I2. In the body of the bit there is mounted a short section of core barrel I3 in thebottom of which there may be a conventional or preferred form of core catcher I4. An upper and somewhat longer section of barrel indicated at I5 is detachably secured to the section I3 such as by a slip joint I6 in which there may be incorporated packing rings I1. The upper section I5 is held centrally of the body Ill by means of arms or spacers I8 welded or otherwise secured thereto. In the upper portion of the body I0 there is formed an outlet opening or window I9 at the bottom of which there is a horizontal plate 20 to which the upper end of the barrel section I5 is threaded or otherwise detachably secured. This plate has secured thereto or integral therewith a deflecting member 2| which extends downwardly and inwardly over the top of the barrel section I5 so that as the core rises through the core barrel in 'the course of normal drilling it will encounter the inclined` surface of the deybody I9 such as by arms or spacers 2li..

fleeting member 2| which will break olf the top of the core into small sections and divert them laterally out of the window or outlet I9.

The breaking off and the diversion of the sections of the core takes place more or less continually during ordinary drilling but when the teeth on the cutters 22 become worn and the bit I I requires replacement it is desirable to recover and retain that portion of the core remaining in the core barrel sections I3 and I5 above the core catcher I4. However, as previously explained on recovery of the bit from the well it is frequently found that the core has become lost and I have determined that this is lost due to the fact that the core in the course of withdrawal of the bit is forced out of the top of the upper core barrel section I5. The reason why the core yis forced upwardly out of the top of the core barrel may depend upon various conditions. vAs previously explained, this may be due to the fact that ithe'drill string is lowered in setting it on slips on the rotary cable in the course of withdrawing the -drill string from the well. -is lowered the relatively close t between the bit vand the well 'walls causes the bit to function Somewhat as 'a vlarge piston forcing uid in the Awell upwardly against the bottom of the core.

When the drill string The loss of the core may also be due to the fact that a pressure di'erential may exist lbetween the under side of the bit II and the exterior of the coring drill collar above the bit. The circulation and the well walls are relatively small the pres- "sure differential created by the discharged circulation fluid 4may be suflicient to force the core upwardy through the core barrel resulting in its los's.

As a means of remedying this loss, I provide a spring holder 23 which is `centered within the This spring holder receives the upper end of a long f compression spring 25, the lower end of which is disposed within a shoe 26 that is urged by the spring 25 to enter the top of the core barrel I section I5.

The bottom surface of this shoe is preferably hard faced asiat 26a. The lower end of the spring holder is threaded as at 27 to the top of a guide 23 for the shoe 2S. This guide is lwelded or otherwise secured to the deecting member 2I and carries a key 29 disposed within fa slot 39 in the shoe 26 so that the shoe will be held against turning although it may be forced upwardly against the action of the compression Y spring 25. The bottom surface of the shoe 2% is preferably inclined so that when in its uppermost position it will function as a diverting member to break o the top of the core and direct it laterally v out of the window or opening I9.

By having the core bit thus constructed in the ultimately be broken off into small pieces which are directed laterally through the window I9. Further movement of the shoe 26 is limited by the engagement of its top with the shoulder 3| on the bottom of the spring holder 23.

Whenever the bit is withdrawn from the well to effect a replacement of the bit II the shoe 2t being pressed downwardly by the compression spring 25 offers a resistance or a restraining l. means bearing on top of the core resisting or prespring 35.

venting its being forced upwardly through th core barrel. Consequently, the residual or remaining core remaining in the core barrel on* discontinuance of drilling will be broken olf by the core catcher I4 and be held against upward movement through the core barrel and through the outlet I9 by the spring actuated shoe.

Other means may be employed for retarding or restraining upward movement of the core through the core barrel. To this end I have il- Vlustrated in Fig. 3 the upper section I5a of the core barrel being divided so as to house a series of `inwardly bowed springs S2. These springs have their inwardly bowed portions arranged on a diameter considerably smaller than the diameter of the core barrel section I5a. In the course of normal drilling operation the core can be forced up through the bowed springs causing them to be flexed outwardly. However, when drilling has been discontinued and the bit is being withdrawn from the well these springs which bear against the sides of the core adjacent the top thereof afford a resistance or retarding means preventing or resisting upward movement of the core and causing it to be retained within the core barrel.

In Fig. 4, the core barrel I5b has likewise been divided to accommodate a resilient choke 33 formed of rubber or rubber-like material having .an internal diameter somewhat smaller than the internal diameter of the core barrel. In normal drilling operations the core passing upwardly through this choke merely expands the choke sufiiciently to enable the core to pass therethrough. However, during recovery of the bit this choke is eective to contract on the core adjacent its upper end to prevent or severely retard upper movement of the core through the core barrel.

In Figs. 5 and 6 still another alternative form of construction is disclosed wherein the top of the upper core barrel section I5c is normally closed by means of a flapper valve 34 urged into closing position by means of a spring y35. This apper valve is shown as being pivoted at 35. In this form of construction also the core can be forced past the apper valve by forcing the flapper valve upwardly against the action of its However, on recovery of the bit the spring 35 urgesJ the flapper valve to close and to thus confine the core therebeneath within the core barrel.

From the above described constructions it will be appreciated that an improved coring bit is provided wherein greater assurance is had for the recovery of the core in that means is provided for resisting upward Ymovement of the core through the core barrel and through the outlet or window I9. Y

Various changes may be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claimt l. A coring bit having a coring drill collar, a core barrel therein, means providing a lateral outlet for the upper end of the core barrel through walls of the drill collar and through which cores in the core barrel may be directed in the course of coring, and means adjacent the upper end of 'I through the core barrel without disintegrating the core before it reaches the outlet.

2.- A coring bit having a coring drill collar, a

core barrel therein, means providing a lateral outlet for the upper end oi the core barrel through walls of the drill collar and through which cores in the core barrel may be directed in the course of coring, and yieldable means adjacent the upper end of the core barrel engageable with the core therein immediately below the outlet from the core barrel for retarding upward movements of the core through the core barrel without disintegrating the core before it reaches the outlet.

3. A coring bit having a coring drill collar, a core barrel therein, means providing a lateral outlet for the upper end of the core barrel through Walls of the drill collar and through which cores in the core barrel may be directed in the course .i

of coring, and yieldable means urged into and normally disposed in the upper end of the core barrel engageable with the core therein immediately below the outlet from the core barrel for retarding upward movements of the core through the core barrel without disintegrating the core before it reaches the outlet.

4. A coring bit comprising a coring drill co1- lar, a core barrel therein, an outlet tting connecting the top of the core barrel to an opening in the wall of the drill collar, and spring actuated means normally urged into a position substantially closing the upper end of the core barrel for resisting upward movements of the core therein.

5. A ooring bit comprising a coring drill collar, a core barrel therein, an outlet tting connecting the top of the core barrel to an opening in the wall of the drill collar, and a spring actuated shoe mounted in the top of the outlet tting and normally urged downwardly into the top of the core barrel.

6. A coring bit comprising a coringdrill co1- lar, a core barrel therein, an outlet fitting connecting the top of the core barrel to an opening in the wall of the drill collar, a spring actuated shoe mounted in the top of the outlet tting and normally urged downwardly into the top of the core barrel, and means for holding the shoe against rotation.

7. A coring bit comprising a coring drill collar, a core barrel therein, an outlet tting connecting the top of the core barrel to an opening in the wall of the drill collar, a spring actuated shoe mounted in the top of the outlet tting and normally urged downwardly into the top of the core barrel, and means for holding the shoe against rotation, said shoe presenting a beveled lower end inclined to direct a core issuing from the core barrel through the outlet fitting.

HAROLD G. BENTSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Taylor Aug. 29, 1950 

